摘要
绿泥石化是诸广南部长江岩体内书楼丘矿床中典型的成矿早期中低温热液蚀变类型。本文利用光学显微镜、电子探针和扫描电镜等手段对矿体外围水平蚀变带内绿泥石进行了综合研究,根据绿泥石的岩相学特征和成因等,将其划分为裂隙充填型绿泥石、黑云母蚀变型绿泥石、长石蚀变型绿泥石、白云母蚀变型绿泥石和球粒状绿泥石5种类型。这5种绿泥石结构类型相同,均为三八面体富铁型绿泥石,分别属于蠕绿泥石、铁镁绿泥石、鲕绿泥石3个种属。5种类型的绿泥石可能形成于成矿早期同一期流体作用之中,形成温度在219~282℃之间,成矿系统的log f_(O2)值为-47.74~-43.69。综合区域上前人研究成果,认为成矿早期流体是以幔源物质为主的壳幔混合流体,其形成与区域上基性岩脉的侵入作用有关,同时,成矿早期流体具有强还原性,为成矿系统提供了还原性化学障,致使主成矿期流体中携带的U6+被还原沉淀成矿。
Chloritization is a typical middle-low temperature hydrothermal alteration type of early ore-forming stage in Shulouqiu deposit of Changjiang rock mass in southern Zhuguang.In this paper,the chlorite in the horizontal alteration zone around the ore body are studied comprehensively by optical microscopy,electron probe and scanning electron microscopy.Based on the lithological characteristics and genesis of chlorite,they are divided into five types:fissure filling chlorite,biotite altered chlorite,feldspar altered chlorite,dolomite altered chlorite and spherical chlorite.The five types of chlorite are all trioctahedral iron-rich chlorite with the same structure type,belonging to three species:vermicular chlorite,ferromagnesian chlorite and uraninite chlorite.Then,the five types of chlorite may have formed in the same period of fluid action in the early ore-forming period,with the formation temperature between 219~282℃and log f_(O2)between-47.74~-43.69.Combined with previous research results in the region,the early ore-forming fluid may be a crust-mantle mixed fluid dominated by mantle-derived materials,with strong reducibility.Its formation is related to the intrusion of regional basic veins,which provides a reducing field for the mineralization system,resulting in the reduction and precipitation of U6+in the ore-forming fluid.
作者
孙国权
范洪海
高永宝
庞雅庆
高飞
薛春纪
范堡程
SUN Guo-quan;FAN Hong-hai;GAO Yong-bao;PANG Ya-qing;GAO Fei;XUE Chun-ji;FAN Bao-cheng(Xi'an Center of Mineral Resources Survey of China Geological Survey,Xi'an 710100,China;CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,China;School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China)
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2024年第5期1313-1327,共15页
Acta Petrologica et Mineralogica
基金
中核集团集中研发项目(LTD1602)
中国地质调查局项目(ZD20220975)。
关键词
绿泥石
地质特征
地质温度计
氧逸度
书楼丘矿床
chlorite
geological feature
geological thermometer
oxygen fugacity
Shulouqiu deposit
